Anticorrosive shipbottom paint



ANTIC IPRRGSEVE SHFJPBQTTQM PAINT William Ii. Francis, Portsmouth, Va.

No Drawing. Application December 8, 1954 Serial No. 474,045

26 Claims. (U. 260-1?) (Granted under Title 35, US. Code (1952), see.265) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

The instant application is a continuation-in-part a plication ofapplication Serial Number 392,060, filed November 13, 1953, which waspermitted to become abandoned in view of and after the filing of theinstant application.

The present invention relates to coating materials, and moreparticularly relates to a corrosion preventive paint suitable forprotecting metal surfaces against the detrimental efiects of sea waterand air, and specifically relates to a substrate anticorrosive paint forships.

Corrosion preventive paints for direct use on metallic surfaces of shipsshould adhere to the ships metal for extended periods of time whenexposed to sea water, the atmosphere, or both, without undergoing rapiddisintegration, cracking, scaling, or peeling. For most effectiveness,the paint film must have a low water absorption and permeability rateand must not be subject to rapid embrittlement and deterioration. Afurther requirement of the paint film is that it inhibit the galvanicand electrolytic action to which steel or aluminum under water is alwayssubjected. An object of the invention is to provide a paint whichsupplies, to an improved degree, the foregoing requirements.

It is a further object of the present invention to provide a protectivecoating for metallic surfaces which dries quickly in from about 1 toabout 3 hours, even under adverse conditions.

Another object of the present invention is to provide acorrosionpreventive paintwhich may be applied without priming to metallicsurfaces to be exposed underwater, the paint itself functioning both asa primer and as a protective coating.

A further object of the invention is to provide a corrosion preventivepaint to which subsequent paint coats adhere satisfactorily.

It is another object of the present invention to provide acorrosion-preventive paint which may be used on a rusted surface andstill have excellent durability and adhesion to a degree not found inother anti-corrosive ships paints. Consequently, preliminary preparationof the surface is minimized.

Still another object of the invention is to provide a paint that hasgood can stability under long storage, and is non-skinning in thecontainer.

A further object'of the invention is to provide a coating of a typedescribed, having the advantages set forth and using a varnish of veryshort oil length in the order of six gallons of drying oil with 100pounds of hard varnish resin. Previous attempts to use an anti-corrosivepaint comprising a short oil varnish on metals submerged in water havenot had satisfactory results because the re sulting paint film was hardand brittle, and would blister so that the paint quickly deteriorated.

Another object of the invention is to provide a coating made with avarnish of which the major constituents are reacted together under hightemperature heat treatment.

Still another object of the invention is to provide a coating utilizinga combination of a hard (260 to 279 F. melting range) and a soft(melting range 41 to 59 F.) coumarone-indene resin in a cookedoleoresinous varnish.

An object of the invention is to provide a varnish vehicle based on aheat product of a hard resin combination of hard coumarone-indene andparaphenyl phenol resins, the hard coumarone-indene being limited,however, to a maximum of close to 50% by weight of the combination butmay be as little as about 10%. The heat product of this combination isimportant in obtaining highly improved performance characteristics in amarine coating.

Other objects and attendant advantages of the present invention will bemade apparent to those skilled inthe art by reference to the followingdetailed description.

In general, a paint comprises a pigment portion combined with a vehicleportion which hardens as the paint. dries to bond the pigment portion tothe painted surface. The vehicle portion consists of a matrix whichforms a binder for the pigment portion, and which is liquified forapplication by heating or by a solvent. The pigment portion of the paintmay include coloring, fillers, toxic agents, passivating agents, etc.,depending upon the purpose for which it is intended. An outline of thegeneral ingredients of a paint is set forth in column 3 of Patent No.2,579,610, dated December 25, 1951. However, the matrix of a substratepaint must adhere to the protected surface and must inturn provide anadequate base for subsequent paint coats. Generally, the matrix of apaint is usually pervious to water to some extent, and it is desirableto provide a pigment portion in the paintwhich will at least retarddetrimental action by such water, preferably by reducing as much aspossible the permeability of the final paint film to water.Additionally, with paints used on ferrous metals, the final paint filmshould inhibit rusting.

In general, a paint embodying the present invention containsnonhardening resins which retard aging and prevent rapid embrittlemen-tof the paint film, thus providing long life and good adhesion to theprotected surface. A liquid composition paint embodying the inventionhas properly proportioned ingredients consisting of a vehicle comprisinga short oil length (six gallon) Varnish with para-phenylphenol-formaldehyde resin and a hard para-coumarone-indene resincombined as the hard resin component in a heat blend with tung oil andlinseed oil, the combination being plasticized with a viscous plastictype of low-melting range para-coumaroneindene resin and dissolved in asolvent; and of a pigment portion containing an ingredient, such as zincchromate, which will release soluble chromate ions in the paint matrix,thereby preventing corrosion of the underlying steel in the event thatsome water penetrates the paint film.

The use of soft para-coumarone-indene resin in the proper proportions asa plasticizer in the novel short oil varnish paint of the invention isimportant. It has been found to reduce the hardness and brittleness ofthe resulting paint film; and it has been found to promote adhesion ofpaint film, thereby eliminating blistering of the paint film on metalssubmarged in water, particularly sea water, for long periods of time. Ofadditional importance is the fact that the ingredients of the paintembodying the invention are fully compatible.

A vehicle in accordance with the present invention is compounded fromingredients in the following proportions by weight:

Vehicle Matrix Only Ingredient Range In Preferred Ranire In PreferredPercent In Percent Percent In Percent Matrix 59 to 61 60 100 Paraphenylphenol formalde- 15.76 to 31.23... 16. 51 26.27 to 52.05--. 27, 51

hyde oil-soluble resin (with melting range 185225 F.). Hardpara-coumaroneindene 3.16 to 17.35... 16. 51 5.26 to 28.92..- 27, 51

resin (with melting range of 260 to 279 F.). Tung oil 8.86 to 12.18...10. 35 14.76 to 20.3... 17. 35 Linseed oil 8.69 to 6.50.-.. 5. 18 6.15 t0.83... 8. 63 Soft para-coumarone-indene' 9.06 to 13.72- 11. 45 15.10 to22.86 19. 10

resin (with 41 to 59 F. melting range). Solvent 39 to 41 XyloL..- 30 to40 Turpentine 0 to 10 In making the matrix, the hardpara-coumarone-indene resin, the para-phenyl phenol-formaldehyde resin,the linseed oil, and the tung oil are placed in a varnish-cookingkettle, and gradually heated as a batch to a temperature of 460 F. (plusor minus F.) in forty (40) to fifty (50) minutes. The mixture is allowedto cook at 460 F. (plus or minus 2 F.) for a period of twenty (20) totwenty-five (25) minutes after which the heat is removed. The softpara-coumarone-indene resin is then added to the hot varnish melt withstirring and the batch or heat product can be called the varnish matrix.

The cooked varnish matrix or heat product is allowed to cool within 16to 24 minutes to approximately 275 F., at which point the xylol andturpentine are added, with stirring during the addition, thus producingthe complete varnish. The varnish is then allowed to cool to roomtemperature and stored. The finished varnish should have a viscosity of0.65 to 0.85 poise at 77 F. and a nonvolatile content of 59 to 61% byWeight.

A pigment portion of a paint in accordance with the present inventionincludes chromate-bearing material which is partly soluble in water toproduce ions to inhibit corrosion, and mica which acts as a physicalbarrier for reducing the permeability of the paint to water.Diatomaceous silica may be added as a filler, and venetian red or ironoxide as a coloring pigment. The pigment portion is compounded in thefollowing proportions by weight:

Pigment Ingredient Range, Preferred,

percent percent Barium chromate, strontium ehromate or zinc chromate50-75 60 Venetian red or iron oxide.-. 5-15 Mica (graphitic or wet groun-30 15 Diatomaceous silica 0-15 15 in the following proportions byweight:

Complete paint Ingredient i Range, Preferred,

percent percent Varnish Vehicle 53. 87-56. 28 55. 08 Pigment 39. 62-45.83 42. 76 Lead linoleate, 26 to 28% lead 0.3-0. 6 .43 Xylol or solventnaphtha 0. 0 3. 5 1. 73

The lead linoleate and a small quantity (about a gallon or two for a100-gallon batch) of the varnish are mixed to a thin liquid consistency,and the lead linoleate liquid is added to approximately half the varnishvehicle, stirring to obtain a uniform dispersion. The pigment is thenadded to this linoleate-varnish mixture, and the Whole is mechanicallyagitated to form a pasty mixture of a suitable consistency for grindingin a paint mill.

Grinding the pigment in the lead linoleate-varnish mixture produces auniform dispersion of the pigment in the vehicle. Any type paint millmay be employed, such as for example a roller or pebble mill; and thegrinding is continued until a fineness of 4 (Hegeman gage) is produced.The ground paint base is then thoroughly mixed with the remainder of thevarnish vehicle and the solvent, and placed in containers for storage oruse.

A paint in accordance with the foregoing has many desirablecharacteristics, especially as compared to prior paints of the samegeneral class. Among these advantages are:

The prepared paint when sprayed as a single film onto a metal surface tobe protected will provide a uniform dry film having a thickness of twoor three mils per coat as compared to one-half that thickness obtainedwith other paints, and a fewer number of coats of the new paint willproduce a required thickness of coating. A coat of paint in accordancewith the invention sets to touch in 10 to 15 minutes and dries in from 1to 2 hours in normal atmospheric conditions. Even under such adversedrying conditions as 40 F. and hLmidity, the paint dries within threehours.

The pigment portion in the paint reduces the permeability of the paintfilm to Water to a small percentage of that of conventional paints.Moreover, the paint film of the new paint on steel has a chemical orpassivating action through the release of soluble chromate ions into anywater which should penetrate the paint film, and so inhibits corrosionof the metal. Actually the pigment portion of the new paint improves thevarnish bnder, apparently acts chemically on the painted steel surface,and improves the water-resistance of the paint film.

The new paint has low permeability to seawater under total immersion,thereby eliminating to a large extent the detrimental galvanic andelectrolytic corrosive action on metal exposed underwater. This propertyis largely because of the unique composition and processing of thebinder portion of the paint, which results in a definitely morewater-resistant binder than any heretofore known. In a comparison testbetween the new paint and the standard anticorrosive paint, Navy Formula14, in which a single coat of 2.5 mils film thickness was applied tosteel panels and then exposed to seawater immersion, the standard paintcoat failed and resulted in extensive corrosion of the steel within 50days, whereas the new paint coating remained intact and continued toprevent corrosion of the coated steel. The rate of water penetrationthrough the film was less than one-third that of a paint can be paintedover after such exposure.

film of the same thickness on thesame steel but obtained with one of thebest paints of the prior art known as Navy Formula 14 Shipbottom Paint.The new paint has low water absorption and permeability propertiesbecause of the water-resistance characteristic of the vehicle binder,and these properties are further enhanced by the physical blockingaction of the flaky micaceous pigment in the composition and by theparticular ratio of the quantity of total pigment to binder used.

The present paint is based on a very short oil varnish and isplasticized with a viscous non-drying neutral resin to promote betteradhesion and flexibility and to prevent the excessive embrittlement ofthe film on ageing that is a common fault of such short oil phenolicresin type varnishes without a special type of plasticizer. Pastexperience has shown that coating films of short oil phenolformaldehyderesin varnishes become very hard and brittle after exposure, and becomedeficient in their adhesion to metal substrates during water immersion.In the case of the subject paint, the deficiencies of the normal shortoil phenolic varnish binder have been largely overcome withoutsacrificing durability and water-resistance properties and at the sametime enhancing the adhesion characteristics of binder.

Although the new anticorrosive paint is designed as the anti-corrosiveundercoat as the basis for the application of an antifouling paint forthe protection of submerged steel surfaces (shipbottoms), it can also bevery satisfactorily used by itself or topcoated with conventionaloutside paint to give long term durability for the protection of metalsurfaces exposed to atmospheric conditions.

The present paint provides a satisfactory undercoat paint for metal tobe coated with a hot plastic (hot melt) type of antifouling, vinylantifouling paint or conventional antifouling paint for underwater use.

The present paint can withstand weather exposure, and The present paintcan be satisfactorily used on parts that operate below water or abovewater or both; and where it is alternately wetted and dried. Because ofthe excellent weathering resistance of the new paint it can be used as atopside protective coating for weather surfaces of metal, as well as ananti-corrosive undercoat for underwater protection of ship-bottoms inwhich the anti-corrosive undercoat serves as an effective basis forapplying an antifouling topcoat paint. This anti-corrosive paint isbifunctional and can serve to protect steel or aluminum structures,either submerged or air-exposed.

Specifically the present paint has a binder based on a very short oilpara-phenyl-formaldehyde resin and hard para-coumarone-indene resinvarnish, plasticized with a soft para-coumarone-indene resin which slowsthe ageing process and prevents early checking and cracking failures inthe paint film and increases the protective value of the paint. Theobjectionable tendency of most anticorrosivc paints of not maintainingsatisfactory pigment suspension and developing settling and hard packingof the pigment during storage of the paint is largely eliminated by theinclusion of lead linoleate which appears to have a peptizing action inthis paint.

Obviously, many modifications and variations of present invention arepossible in the light of the above teachings. It is therefore to beunderstood that, within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

Having thus described the invention, What is claimed is:

1. A vehicle for an anti-corrosion paint for use on metallic surfaces,said vehicle comprising a matrix having a heat reaction product ofingredients comprising 26.27 to 52.05 percent para-phenylphenol-formaldehyde resin, and 5.26 to 28.92 percent hardpara-coumarone-indene resin having a melting range of 260 to 279 F., anda plasticizer of 15.1 to 22.86 percent soft para-coumaroneindene resinhaving a melting range of 41 to 59 F., all percentages being by weightof matrix, and comprising varnish oil in a quantity to make said vehiclea short o i l length varnish vehicle, said varnish oil comprising tungoil as a major part thereof.

2. A vehicle as defined in claim 1 with lead linoleate as a drying andpeptizing agent.

3. A vehicle for an anti-corrosive paint for use on metallic surfacescomprising a matrix having a heat reaction product of 26.27 to 52.05percent para-phenyl phenol-formaldehyde resin, 5.26 to 28.92 percenthard para-coumarone-indene resin having a melting range of 260279 F.,14.76 to 20.3 percent tung oil, and 6.15 to 10.83 percent linseed oil,said matrix having a plasticizer of 15.1 to 22.86 percent softpara-coumarone-indene resin having a melting range of 41 to 59 F., allper centages being-by weight of matrix.

4. A vehicle as defined in claim 3 with lead linoleate as a drying andpeptizing agent.

5. A vehicle as defined in claim 3 wherein said matrix comprises about60 percent of said vehicle, the remainder being a solvent, a major partof which is xylol.

6. A vehicle as defined in claim 5 wherein said solvent consists of 30to 40 percent xylol and 0 to 10 percent turpentine by weight of vehicle.

7. An anti-corrosion paint for use on metallic surfaces, comprising avehicle including para-phenyl phenolformaldehyde resin, hardpara-coumarone-indene resin having a melting range from about 260 F.279E, tung oil and linseed oil, the vehicle plasticized with a softpara-coumarone-indene resin having a melting range from about 41 F.-59B, said vehicle being combined with a pigment containing a partlywater-soluble chromate from the group consisting of zinc chromate,barium chromate and strontium chromate, said tung oil and linseed oilbeing in such quantity as to make said vehicle a short length varnishvehicle.

8. An anti-corrosion paint as defined in claim 7 including leadlinoleate as a drying and peptizing agent.

9. An anti-corrosion paint for use on metallic surfaces as defined inclaim 7 but further characterized by said pigment containing mica.

10. An anti-corrosion paint as claimed in claim 9 wherein said pigmentincludes 50 to 75 percent of an ingredient from said group and 15 to 30percent mica.

11. An anti-corrosion paint for use on metallic surfaces comprising53.87 to 56.28 percent of a short oil length varnish vehicle by. weightof paint; said vehicle including tung oil and including a heat reactionproduct of 15.76 to 31.23 percent para-phenyl phenol-formaldehyde resinand 3.16 to 17.35 percent hard para-coumarone-indene resin having amelting range of 260 to 279 F., and a plasticizer of 9.06 to 13.72percent soft para-coumaroneindene resin having a melting range of 41 to59 F., percentage being by weight of vehicle; said paint comprising39.62 to 45 .83 percent pigment by weight of paint; said pigmentincluding 50 to 75 percent of an ingredient from the group consisting ofbarium chromate, strontium chromate and zinc chromate, and 15 to 30percent mica, said percentages being by weight of pigment.

12. A paint as defined in claim 11 including .3 to .6 percent leadlinoleate.

13. A paint as claimed in claim 11 wherein said pigment also includes 5to 15 percent coloring and O to 15 percent diatomaceous silica, saidpercentages being by weight of the total pigment.

14. A paint as claimed in claim 11 wherein said vehicle includes 8.86 to12.18 percent tung oil, 3.69 to 6.50 percent linseed oil, andsubstantially 40 percent solvent, said percentages being by weight ofvehicle.

15. A method of compounding an anti-corrosive paint vehicle comprisingcooking a batch containing by weight of the matrix of the vehicle 26.27to 27.51 percent paraphenyl phenol-formaldehyde resin, 5.26 to 27.51percent para-coumarone-indene resin with a melting range of 260-279 F.,14.76 to 17.25 percent tung oil, and 6 .15

to 8.63 percent linseed oil at a temperature of about 460 F., for about20 minutes, and subsequently adding 15.10 to 22.86 percentpara-coumarone-indene resin with a 41 59 melting point.

16. An anti-corrosive paint as claimed in claim 14 but furthercharacterized by said paint including a small quantity of leadlinoleate.

17. An anti-corrosive paint for use on metallic surfaces comprising53.87 to 56.28 percent vehicle by Weight of paint; said vehicleincluding a heat reaction product of 15.76 to 31.23 percent para-phenylphenol-formaldehyde resin, 3.16 to 17.35 percent hardpara-coumarone-indene resin having a melting range in from 260 to 279F., 8.86 to 12.18 percent tung oil, and 3.69 to 6.50 percent linseedoil, and a plasticizer of 9.06 to 13.72 percent softpara-coumarone-indene resin having a melting point in a range from about41 to 59 F., and substantially 40 percent solvent, said percentages ofvehicle ingredients being by weight of vehicle; said paint comprising39.62 to 45.83 percent pigment by weight of paint, said pigmentcomprising an ingredient from the group consisting of barium chromate,strontium chromate and zinc chromate.

18. An anti-corrosive paint as claimed in claim 17 but furthercharacterized by said paint including a small quantity of leadlinoleate.

19. A paint comprising a heat reaction product of para-phenylphenol-formaldehyde having a melting range of about 185 F. to 225 F.,hard para-cournarone-indene resin having a melting range of about 260 F.to 279 F., soft para-coumarone-indene resin having a melting range ofabout 41 F. to 59 F., and a varnish oil comprising tung oil as a majorcomponent, said varnish oil being in such quantity as to make saidvehicle a short oil length varnish vehicle, said paint comprising apigment comprising a partly water-soluble chromate from a groupconsisting of zinc chromate, barium chromate and strontium chromate,said pigment further comprising mica.

20. A matrix for a short oil length varnish vehicle, by Weight saidmatrix comprising from 20.91 to 31.13

. percent varnish oil a major part of Which is tung oil,

the balance of said matrix comprising essentially 26.27 to 52.05 percentpara-phenyl phenol-formaldehyde, resin having a melting range from about185 F. to 225 F., 5.26 to 28.92 percent hard para-coumarone-indene resinhaving a melting range of about 260 F. to 279 F., and 15.10 to 22.86percent soft para-coumarone-indene resin having a melting range of about41 F. to 59 F.

21. A matrix as defined in claim 20 with lead linoleate as a drying andpeptizing agent.

22. A matrix as defined in claim 20 but further characterized by saidtung oil being from about 14.76 to 20.3 percent of said matrix.

23. An anti-corrosive paint comprising a matrix by weight comprisingfrom 20.91 to 31.13 percent varnish oil a major part of which is tungoil, the balance of said matrix comprising essentially 2627 to 52.05percent paraphenyl phenol-formaldehyde resin having a melting range fromabout F. to 225 F., 5.26 to 28.92 percent hard para-coumarone-indeneresin having a melting range of about 260 F. to 279 F., and 15.10 to22.86 percent soft para-coumarone-indene resin having a melting range ofabout 41 F. to 59 F., a solvent for said matrix and a pigment, thematrix and solvent comprising about 53.87 to 56.28 percent by Weight orthe paint, the pigment comprising about 39.62 to 45.83 percent by weightof the paint, said pigment comprising mica and an ingredient from thegroup consisting of barium chromate, strontium chromate, and zincchromate.

24. A paint as defined in claim 23 including .3 to .6 percent leadlinoleate.

25. A method of compounding an anticorrosive short oil length varnishpaint having a matrix, comprising gradually heating to about 460 F. inabout 40 to 50 minutes as a batch 26.27 to 52.05 percent phenylphenolformaldehyde oil-soluble resin, 5 .26 to 28.92 percent hardpara-coumarone-indene resin having a melting range in from 26 to 279 F,20.91 to 31.13 percent of a vehicle oil the major part of which is tungoil; cooking the batch at about 460 F. for about 20 to 25 minutes; andthen adding 15.10 to 22.86 percent soft para-coumarone-indene resinhaving a melting range in about 41 to 59 F. to the batch while hot;thereby providing the paint-matrix, said percentages being by weight ofmatrix.

26. A method as defined in claim 25 but further characterized by coolingsaid matrix to about 475 F. in about 16 to 24 minutes, and then adding athinning solvent.

Gordon et al.: Surface Coatings & Finishes, pages 28, Chem. Pub. Co.,1954.

1. A VEHICLE FOR AN ANTI-CORRISON PAINT FOR USE ON METALLIC SURFACES,SAID VEHICLE COMPRISING A MATRIX HAVING A HEAT REACTION PRODUCT OFINGREDIENTS COMPRISING 26.27 TO 52.05 PERCENT PARA-PHENYLPHENOL-FORMALDEHYDE RESIN, AND 5.26 TO 28.92 PERCENT HARDPARA-COUMARONE-IDENE RESIN HAVING A MELTING RANGE OF 260* TO 279*F., ANDA PLASTICIZER OF 15.1 TO 22.86 PERCENT SOFT PARA-COUMARONEINDENE RESINHAVING A MELTING RANGE OF 41* TO 59*F., ALL PERCENTAGES BEING BY WEIGHTOF MATRIX, AND COMPRISING VARNISH OIL IN A QUANTITY TO MAKE SAID VEHICLEA SHORT OIL LENGTH VARNISH VEHICLE, SAID VARNISH OIL COMPRISING TUNG OILAS A MAJOR PART THEREOF.